The disgraced cycling icon speculated in social media that Froome and his team might be "too strong to be clean." Armstrong's tweets can be accessed here.

Earlier that day, Froome, Porte, and Sky blazed pass the competition on the first summit finish of the race. A select group of favorites managed to ascent with them at La Pierre-Saint-Martin, but Froome saved his best efforts for the last slope of the race and no one could keep pace.

Daniel McMahon of Business Insider writes, "With his dominating performance Froome extended his lead and put his stamp on the world's premier bicycle race as the strongest man and clear favorite to win in Paris on July 26, even though there are several tough mountain stages still to go."

The present success of the 30-year-old Kenyan-born British cyclist prompted Armstrong to tweet out "Clearly Froome/Porte/Sky are very strong. Too strong to be clean? Don't ask me, I have no clue."

The tweet has since then garnered four thousand retweets, with one Twitter user commenting "@lancearmstrong you destroyed the reputation of this great race and now you try to harm it further by accusing others? Please stop."

Armstrong then responded "@danieljcastille I'm not accusing anyone In [sic] fact, quite the opposite. I'm not interested (nor do I have the credibility) to opine there."

In his autobiography, published last year, Froome spurned Armstrong:

"I am not a student of Lance Armstrong or that period in cycling. He doesn't interest me and that era doesn't interest me... You think I'm guilty. Can you prove it? No. I know I'm clean. Can I prove it? No. You heard it all before from Lance Armstrong. Well, I'm not Lance Armstrong. You won't get fooled again. Not by me you won't, ever."

Also on Tuesday, BBC Sport stated that Froome's computer files with his performance data had been hacked.

Froome has been scrutinized since his Tour win in 2013, yet he has always insisted upon his purity.

In hindsight, the US Anti-Doping Agency found that Armstrong and his team ran "the most sophisticated, professionalized and successful doping program that sport has ever seen." He was stripped of his achievements after it was discovered that his victories were aided by a variety of performance-enhancing drugs.

Armstrong is facing a $100 million lawsuit from a former teammate, Floyd Landis, which could bring him financial ruin.